Immunologic production of antiangiotensin. I. Preparation of angiotensin-protein complex antigen.
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Angiotensin II was coupled with bovine gamma-globulin (BGG) through the following series of reactions. See PDF for Structure By determinations of the aromatic amine and tyrosine contents of p-aminobenzoylangiotensin II, the number of p-aminobenzoyl residues introduced per molecule of angiotensin II was calculated. Absorption spectra (between 250 and 500 mmicro) of BGG complexes of p-aminobenzoylangiotensin II and six different para substituted aromatic amines were compared. Specific activities (dog units/millimicromole) of the different intermediate products were determined. Presence of a terminal, free amino group does not appear to be an absolute requirement for the biological activity of angiotensin II, since substitution of a p-aminobenzoyl radical in this group yields a product with 40 to 50 per cent of the activity of the parent compound. Angiotensin I, on the other hand, is completely inactivated under identical circumstances. Possible implication of this finding has been discussed. (+info)
Immunologic production of antiangiotensin. II. Production and detection of antiangiotensin.
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The parenteral administration of benzoylangiotensin II-azo-BGG to rabbits produced an antiserum with antiangiotensin activity. Antiangiotensin inhibited the biological action of p-aminobenzoylangiotensin II, valine(5)-angiotensin II (free acid form), isoleucine(5)-angiotensin II and valine(5)-angiotensin II (amide form), but it was totally inert towards angiotensin 1. Antiangiotensin activity was distinguished from that of serum angiotensinase by the following observations: (a) an angiotensinase-free gamma-globulin fraction contained antiangiotensin, (b) angiotensinase inactivated angiotensin II (both the amide and free acid forms) and angiotensin I in contrast to the remarkable specificity for angiotensin II exhibited by antiangiotensin. Serological demonstration of antiangiotensin included: (a) a comparison of its precipitin reaction with the angiotensin BGG complex with the reaction with BGG alone, (b) the partial inhibition of the precipitin reaction with the angiotensin BGG complex by angiotensin II, (c) a precipitin reaction with a different angiotensin II protein complex (cat serum). Angiotensin II administered parenterally as the free polypeptide was not antigenic. (+info)
Some pharmacological actions of synthetic analogues of angiotensinamide.
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In order to evaluate the importance of some structural features of asparagyl(1)-Valyl(5)-angiotensin II (angiotensinamide) for its pharmacological actions, the relative potencies of angiotensinamide and five peptide analogues were studied on the blood pressure of the rat, the isolated rat uterus and the isolated guinea-pig ileum. All the modifications of the angiotensinamide structure that were studied led to a decrease of potency which, however, was not the same on all three preparations. The importance of the guanido group, the phenolic group and the length of the peptide chain for the pharmacological activities of these peptides is discussed. (+info)
Actions of some peptides on bronchial muscle.
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The decapeptide kallidin-10, substance P and angiotensin increased the resistance of guinea-pig lungs to inflation; lysine- or arginine-vasopressin and oxytocin were inactive. Acetylsalicylate antagonized this action of kallidin-10, as it does that of bradykinin, but it failed to antagonize substance P or angiotensin. Bradykinin also increased resistance to inflation of rabbit lungs and, to a lesser extent, rat lungs. It caused a relatively slow contraction of guinea-pig tracheal and bronchial muscle in vitro, but it did not contract isolated rabbit, dog or human bronchus. The relative potencies of different substances on different bronchial test preparations, and also in different species, were not parallel. (+info)
Pharmacological actions of pepsitensin.
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In confirmation of the results of Croxatto and his co-workers, plasma proteins incubated with pepsin yielded a substance (pepsitensin) with pressor activity. Euglobulin gave a much higher yield than the other plasma protein fractions. Incubation for 4 hr at pH 4 gave high yields of pressor activity (pepsitensin) but no antidiuretic activity; incubation of euglobulin for 4 hr at pH 2.5 yielded extracts with antidiuretic as well as pressor activity. Incubation for 8 to 11 hr at pH 2.5 produced the highest yield of both activities. Further incubation, at the same pH, up to 20 hr caused a rapid decline in the pressor activity of the extracts, but the antidiuretic activity was much more resistant to destruction by pepsin. Pepsitensin was found to be very soluble in water and poorly soluble in organic solvents. It is not inactivated by thioglycollate. In blood pressure assays some animals did not respond to pepsitensin, and nephrectomized (17 to 24 hr) rats were found to be more suitable preparations. Pepsitensin was shown to exert pressor effect by direct action on the blood vessels. Its pressor action could be differentiated from that of tyramine, dimethylphenylpiperazine, nicotine, noradrenaline and Pitressin but not from that of angiotensin. The isolated guinea-pig ileum and the rat uterus were equally sensitive to angiotensin and pepsitensin. In paper chromatograms, in the solvent system butanol-acetic acid-water, the R(F) of pepsitensin was very similar to that of angiotensin. (+info)
Stimulation of intestinal nervous elements by angiotensin.
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The stimulation of nervous elements in the intestine by the polypeptide angiotensin has been examined. Comparisons between nicotine, a neurotropic agent, acetylcholine which exerts principally a musculotropic action and angiotensin have been made by examining their interactions with hexamethonium and the anticholinesterase 1,5-di-(p-N-allyl-N-methylaminophenyl)pentan-3-one dibromide in both the rabbit and guinea-pig ileum. The effect of atropine on the responses of the guinea-pig ileum and botulinum toxin on the responses of the rabbit ileum to angiotensin was also tested. The results show that angiotensin causes most of its contractile response in both the guinea-pig and rabbit ileum by an indirect action, through the stimulation of nervous tissue. (+info)
Home blood pressure monitoring in diabetes.
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Forty three children with diabetes were recruited to evaluate home blood pressure monitoring using an electronic oscillometric sphygmomanometer (Philips HP5330). This device was found to be simple to use and reliable. It fulfilled the accuracy criteria of the American Association for the Advancement of Medical Instrumentation for both systolic and diastolic blood pressure and those of the British Hypertension Society for systolic blood pressure. Thirty eight children successfully measured their own blood pressure at home and taught other family members to do the same. The results indicate that home blood pressure monitoring is of value in the management of diabetic children. (+info)
Synergistic effects of the MTHFR C677T polymorphism and hypertension on spatial navigation.
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